McDonald's is giving away free fries every Friday. Here's how to get some.

McDonald’s is offering free french fries every Friday for the rest of the year.

Customers need to download and register for the McDonald’s app and use it to make a purchase in order to be eligible for the deal.

McDonald’s is offering the same perk on soft drinks mid-week. Any Tuesday or Thursday for the rest of the year, customers can claim one free soda when they spend $US1 or more and order through the app.

McDonald’s just made Fridays even more appealing.

The fast-food chain is extending its National French Fry Day deal and giving away free medium fries every Friday to customers who spend $US1 or more for the rest of the year.

There’s one catch: you’ll need to download and register for the McDonald’s app and use it to make a purchase in order to be eligible for the deal.

And it’s not just french fries: McDonald’s is also offering the same perk mid-week on soft drinks. Every Tuesday or Thursday for the rest of the year, customers can claim a free soda when they spend $US1 or more and order through the app.

The new deal is a way to draw customers in to its mobile-ordering service, which the fast-food chain launched in 2017 and is putting major investments toward improving.

As foot traffic slows, many fast-food chains are looking to grow sales by encouraging customers to order on their smartphones.

According to data from the NPD Group, the number of orders being placed via mobile apps skyrocketed by 50% in US restaurants in 2017. Business Insider Intelligence predictsthat by 2020, mobile order-ahead will account for 10.7% of all quick-service restaurant (QSR) sales.

Ordering ahead allows users to save time by skipping lines and having food ready and paid for upon arrival at a restaurant.